Shafts or axles of rotationally driven systems are subjected to torsional tensions which lead to elastic deformations due to the non-ideal rigid material properties of the shaft or axle. From a physics viewpoint, the drive unit can be conceptualized as two ideal, rigid masses which are connected by a spring. One mass is the inert mass of the motor, while the other mass is the inert mass of the load. A drive unit such as this has intrinsic oscillations which adversely affect the regulation of a particular system, for example a machine tool or a robot. The oscillations also strongly stress the affected material.
In systems in which the particular load is moved either rotationally or linearly, such as commercially available machine tools, it is possible to measure a difference speed or a difference position between the load shaft and the motor shaft. This could be done by one sensor on the motor and another sensor on the load. Sensors are always present on the motor shaft in regulated systems. For the regulation of a spring moment or a difference speed, additional sensors on the load shaft are required. This measure, however, is very expensive.
It is often impossible to attach a direct measuring system on the load. An example of this is robots which are able to move their hand or their gripper to any given point of a predetermined three-dimensional working space.
The problem posed is to provide a method for regulating a spring moment and a difference speed so that the occurring spring moment and the difference speed are determinable without directly measuring the speed of a load shaft or the load position.